Method for weighting regenerated cellulose



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WILHJELM WEBER, F HACKENSAC AND EUGENE SGHAEFE'R, 0:5 ENGLE- 'WQQD, i l-EH7 JERSEY, ASSIGNOBS T0 MAE WOOD CHEMICAL WORKS, 01 MZAYWOOD,

dhRSEY, A COEEGEATION OF NEW JERSEY HETEIOD BT03." WEIGHTHJG} Flo Application filed July 3,

The present invention relates to a method for weighting regenerated cellulose which is now brought on the market as artificial silk under various trade-names, the object oi the invention loeing to provide a method by which it is possible to weight such artificial silk similarly as is done with natural silk long since.

Artificial silk is relatively low in weight and garments made from such artificial silk hang loosely on the body and are, therefore, not of such attractive appearance as one would expect on account of the silk-like properties of the artificial silk. It is, therefore, a long felt want to weight artificial silk similarly as natural silk and the silk dyers hoped to accomplish this end by the same processes as applied in the weighting of natural silk. 'llt has been found impossible, however, to weight artificial silk in the manner adopted for natural silk, in which the weighting often amounts to several hundred percent of the fiber. l'n so far as proposals for this purpose exist they are confined to weighting artificial silks up to approximately 5 percent.

(has oil us, Friedrich W. Weber, has described in his co-pending application, Serial No. 425,707, filed February 3, 1980, the weighting of both natural and artificial silks of all kinds with insoluble compounds of tin and of rare earth metals, while both oi us have describe in our co-pending application, Serial No. 515,138, filed February 11, 1931, a method of weighting both natural and artificial silks of all kinds with insoluble compounds oil tin and such of metals other than a rare earth metal, the chloride of which is soluhle in water and the phosphate of which is insoluble therein; the method of our application also allows to combine the insoluble compounds of the rare earth metals with those of other metals.

lln our atoresaid application Serial No. 515,138 we have shown that both natural and artificial silk may successfully be weighted with a solution, made by dissolving the carbonate of a metal, forming a soluble chloride and an insoluble phosphate, in the solution ot a salt of a weighting metal, such as tin, loy subjecting the silk first to the aforesaid lll) dell) REGENWATED CELLULO$E 1931. Serial filo. 548,7Gll.

de-acidified solution and then subjecting the silk to the solution 01" a salt, forming an insoluble salt with the metal, such as tin.

We also have shown in aforesaid application, Serial No. 515,138, that the salt solution of the weighting metal, such as tin, maybe de-acidified with the mixture of the carbonate of a rare earth metal and that of an other metal, forming a soluble chloride and an insoluble phosphate; and we have, furthermore, shown in said application that for the de-acidification of this weighting metal salt solution, such as tin-tetrachloride solution, we are not restricted to the carbonate form of the metals, but that any other form of their basic compounds, such as their hydroxides and the like, may be applied with like success, but that also certain salts, in which the metal oxides display an acid character, "for instance, sodium zincate,-sodium plumbate, sodium aluminate, sodium stannate, etc. may be applied with good success. We also pointed out that it natural or artificial silk is to be dyed in dark shades, insoluble metal salts of dark colors are very desirable in the weighting of the silk, as a ore-treatment for, or part of the dyeing process.

While our investigations have shown that in both natural and artificial silks deposits of substantial amounts of insoluble compounds of tin and of other metals can be brought about, so that in'eaoh case a con siderahle weighting has taken place, which goes far beyond what was possible in the prior act, we have also noticed that the various kinds of artificial silk take rather difierently to the weighting materials.

The present invention is based on aforesaid observation and relates articularly to the weighting of artificial sil which is generally known as viscose and to similar kinds chemically closely related to viscose, i. e. artificial silks, which are substantially either cellulose, or cellulose-hydrate. The chief representatives of this type of artificial silk are made by dissolving cellulose, or cotton, in a suitablesolvent, for instance in a solution of copper hydroxide in ammonia or in the form of its sodium compound in carhon disulphide,

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whereby a solution of cellulose xanthogenate is obtained.

The artificial silk is obtained from the solutions, of the cellulose in cuprammonium as well as from the cellulose Xanthogenate by discharging a fine. stream of the solution into a precipitating agent, mostly of acid character, such as the sulphuric acid, whereby the cellulose solution is decomposed and a fine silk-like thread is obtained. This fine thread consists, as already stated, mainly of cellulose hydrate.

Another closely related artificial silk is the collodion silk, in its denitrated state into which it is brought to avoid its inflammation and explosion ;it is then considered practically pure cellulose, its constitution being, apparently not yet, absolutely definitely established.

In our investigation of the silk weighting properties of these artificial silks, consisting of cellulose regenerated from cellulose solutions, we found that there are only slight variations intheir response, which variations may have their cause in the often great differences of the denier in which these artificial silk threads were made, the viscose, however, showing the slightest variations and standing also in this respect between the collodion and cuprammonium silk.

While the aforesaid artificial silks, consistin of cellulose regenerated from its solution, in ly answer the requirements of the method described in the aforesaid applications, Serial Nos. 425,707 and 515,138, we have found that they display a rather surprising preference for zirconium compounds in combination with tin compounds. On the ound of ,these observations we have succeeds in establishing a precise and promptly acting method for the weighting of artificial silk consisting of regenerated cellulose and in obtaining products of considerable increase in Weight,

, elasticity, strength, and great luster.

Inasmuch as we have already'vp'ointed out above that of the various kinds of regenerated cellulose, viscose gives the most uniform results, we shall state how we proceed to carry our invention into effect and shall describe the same by giving as an example how we weight viscose.

Example A solution of 750 gr. tin-tetrachloride of 50 Be. is heated to approximately C. and

then 50' gr. zirconium carbonate are entered into the same; the carbonate dissolves and the solution is then diluted with water to one (1) asaaaos less, absolutely clear and is, therefore, well suitable for weighting purposes. We found that we can weight with it equally well viscose in the form of skeins as in the form of piece goods, that the solution can beused over and over again without any regeneration or adjustment, and that the goods after each immersion show practically the same increase in weight, particularly if we proceed in the following manner:

The weighed viscose is soaked for 1-2 hours in the solution while the same is occasionally agitated. 'llhereupon the goods are taken out, the surplus of solution is removed mechanically in any of the well known ways, they are then washed with water and introduced into the solution of an alkali-metal phosphate, silicate, tungstate, molybdenate, such as di-sodium-phosphate or sodium silicate, respectively, etc., including also the corresponding ammonium salts in the group of aforesaid salts.

Iii we, :for instance, pass the goods thus treated into a (ii-sodium phosphate solution to fix the tin and zirconium in the form of their phosphates upon the viscose, we find that the goods, well washed and dried after each passage through the sodium phosphate, show an increase in weight of 30% after the first, of 50% after the second and of after the third passage.

The process described above is remarkable also for the fact that the viscose may be treated not only when raw, but also when it is al-' ready dyed. We'have established by experiments that the same weights may be obtained by our processregardless whether the viscose was raw or dyed. Moreover dyed viscose,submitted to our new weighting process described above, displays substantially the same shade of coloras before the weighting so that any quanti of dyed viscose may be weighted without anger to its marketability.

The products obtained by our process also overcome the sometimesprobably not quite unfounded prejudice which decries artificial silk as not being sufliciently water-proof for everyday purposes which require that the article, made of artificial silk, be washed.

Theehereinafter stated results of a strenuous test of woven viscose fabrics in regard to their resistance to soap fully prove that fabrics, made of artificial silk, such as viscose, and weighted byour new process, are unmistakeably equal to any other textile fabric.

To test the viscose fabrics we proceeded as follows:

We prepared a soap solution, containing 5% of practically neutral olive soap, and heated the same up to 70 C. The viscose fabrics, which we submitted to the test, were weighted by our new process, described above, and carried a deposit of the phosphate of tin and zirconium; each of the pieces of the tabgoods in the dyeing art.

hides were accurately weighted and then immersed for 5 hours into the hot soap solution, The .iabrics in the soap solution were agitated in certain, relatively short intervals and the temperature maintained at ?0 C. The pieces where then removed from the soap solution and well washed twice with water, then squeezed to remove the water, washed again and then dried until the weight remained constant, When this stage was reached, each of the tested pieces of fabric showed exactly the same weight as before the test; there was neither a loss, which eventually might have been anticipated by a dissolving action ofthe soap on the phosphates carried by the viscose, nor any gain. The only effect due to the soap on the viscose alabrics was that the fabrics felt softer than before, which fact'is nits in accordance with the experience made 111 the soaping of finished ln connection with the above facts it appears of importance to state that in the prior art of silk weighting the skeins of silk, after they were soaked for some time in at tin-tetrachloride solution-were deprived as much as possible of the surplus of the same before the goods were washed with water. This was preferably done by centrifuging the wet skeins and the reason for this operation was the wish to avoid the loss of the adhering tintetrachloride because when the washing was done, unnecessarily much tin-tetrachloride was lost in the washing water from which it could hardly profitably be recovered. Furthermore, the excess of the adhering tetrachloride would unduly delay or extend the time required for completing the hydrolysis of the tin-tetrachloride actually kept in the fiber.

ln our new process, however, the de-acidified tin-tetrachloride ofiers much more favorable conditions because we apply a solution in which the salt is already contained in a basic form, which is inclined to complete its hydrolysis more readily sothat after the soaking oi the fibers it is not absolutely necessary to remove the excess of the basic tin-tetrachloride.

"ll hat we claim is: V

l. The method for weighting artificial silk fiber in the form of cellulose hydrate rene erated from solutions of cellulose, said met 0d consisting in actin on the fiber with the aqueous solution, containin basic salts of tin and of zirconium, then was ing the fiber with water, and subjecting the fiber, thus treated to solution of a salt capable of forming an insoluble salt with tin and zirconium.

2. The method forweighting artificial silk fiber in the form of cellulose hydrate regenerated from solutions of cellulose, said method consisting in acting with zirconium carbonate on the solution of tin-tetrachloride thereby obtaining a clear solution of basic tin-chloride and of basic zirconium chloride, subjecting the cellulose hydrate to aforesaid clear solution, washing the cellulose hydrate with water, and acting then on the thus treated cellulose. hydrate with the solution of metal salt forming an insoluble salt with the tin and zirconium compound contained inthe cellulose hydrate fiber.

3. The method for weighting artificial silk fiber in the form or cellulose hydrate regenerated from solutions of cellulose, said method consisting in acting with zirconium carbonate on the solution oi tin-tetrachloride thereby obtaining a clear solution of basic tin-chloride and of basic Zirconium chloride, subjecting the cellulose hydrate to aforesaid clear solution, washing the cellulose hydrate with water, and acting then on the thus treated cellulose hydrate with the solution of an alkali-metal phosphate.

4. The method for weightin artificial silk fiber in the form oi cellulose ydrate regenerated from solutions of cellulose, said method consistin in acting with zirconium carbonate on the solution of tin-tetrachloride thereby obtaining a clear solution of basic tin-tetrachloride and of basic zirconium chloride, subjecting the cellulose hydrate to aforesaid clear solution, washing the cellulose hydrate with water and acting on the cellulose hydrate with the solution of di-sodium phos I 5. The method for weighting viscose-silk, said method consisting in acting with air conium carbonate on the solution of tin-tetrachloride thereby obtaining a clear solution of basic tin chloride and of basic zirconium chloride, subjectin the viscose to aforesaid clear solution, was ing the viscose with water, and acting then on the thus treated viscose with the solution of a metal salt forming an insoluble salt with the tin and the zirconlum compound contained in the viscose fiber.

6. The method for weighting viscose-silk, said method consisting in acting with zirconium carbonate on the solution of tin-tetrachloride thereby obtaining a clear solution of basic tin chloride and of basic zirconium chloride, subjecting the viscose to aforesaid clear solution, washing the viscose with water, and acting then on the thus treated viscose with the solution of an alkali-metal phosphate.

7. The method for weighting viscose-silk, said method consisting in acting with Z11- conium carbonate on the solution of tin-tetrachloride thereby obtaining a clear solution of basic tin chloride and of basic zirconium chloride, subjecting the viscose to aforesaid clear solution, washing the viscose with water, and acting then on the thus treated viscose with the solution of di-sodium phosphate.

8. As a means of weighting artificial silk fiber in the form of cellulose hydrate regen- 4 mesgme embed from solutions of cellulose, an aqueous solutlon of baslc chlorldes of hn and of Z11- comum.

In witness whereof we have hereunto set 5 our hands.

FRIEDRICH WILHELM WEBER. EUGENE SQHAEFER. 

